Limb Lengthening

Limb Lengthening

After it was discovered that bone length could be lengthened and angular values could be changed to eliminate leg length inequalities caused by various factors or to treat angular deformities, the first lengthening surgeries began with the correction of deformities and lengthening of bone lengths, particularly in patients with bone dysplasia resulting in severe short stature (dwarfism, etc.). These treatments, which are exceedingly difficult and risky for physicians in Turkey, have resulted in the creation of more bearable procedures in modern life and have found a more wider application area as demand has increased over time.

Although there is no absolute short stature value for stature lengthening surgery, it is accepted that stature lengthening surgeries can be performed for short stature of 150 cm in women and 160 cm in men and below .

The basic philosophy of lengthening (bone) is based on the principle of increasing the distance between the two ends of a broken bone very slowly (distraction) and lengthening the union tissue by deceiving it.

Historically, lengthening surgeries were first performed with the help of devices called External Fixator (Three-Dimensional Ilizarov and similar Fixators or Monolateral Fixators) in order to lengthen short bones or bring the angles of deformed bones into anatomical shapes. With the help of nails or wires that are placed from the outside of the body and extend to the bones, the healing tissue between the bones is controlled and extended in length and angle with the help of external screws. While calculations are made in bone lengthening (although it may vary depending on the biological factors of the patient), it is thought that an elongation of 1 cm will take approximately 1 month. Of course, in this case, a height extension of about 8-9 cm; in case of a possible delay in boiling;

The contribution of theoretical knowledge is important in the development of new methods. Because a 1 cm elongation takes a period of about 1 month, but not all of it is elongated. Therefore, it is necessary to examine bone lengthening in two separate phases. While the first phase is the elongation/lengthening phase called distraction, the second phase is the consolidation phase and is the waiting period for the elongated union tissue (regenerate) to become strong enough to take a load, which generally corresponds to approximately 2 times the lengthening phase. In this case, to give an example, in a 9 cm lengthening process, the first 3 months is the lengthening period (distraction) , and the 6 months after the elongated bone reaches a level of hardness sufficient to carry the load (consolidation).This theoretical knowledge, combined with the advancement of medical techniques, encouraged the development and application of new methods.

At this point, it is necessary to give information about two main methods.

The first is LON-Lengthening on Nail , also known as the Combined Method , and the second is lengthening surgeries using Magnetic Nails . The basic philosophy here is to ensure that the strengthening period of the bone (which is at least 2 times the consolidation phase-lengthening time) after the lengthening process is more tolerable for the patient.

In the combined method (LON-Lengthening on Nail) , after the controlled fracture line created in the bone is filled with a thick conventional nail (intramedullary nail)  that fills the space inside the bone called the long bone medulla, nails placed on both sides of the fracture ends from the skin to the bone and external support and extension Apparatuses (Fixator) to extend the bone length by opening the distance between the bones (eg 90 days (3 months) for an 8-9 cm elongation), with a second but smaller surgical procedure, removing the fixator outside the skin and removing the thick nail inside the bone; in the elongated state of the bone; It is the process of locking it with screws so that it cannot be seen from the outside.

The third and most modern method is called Cosmetic Extension or Magnetic Nail Extension , and it is the technique in which the extension process is carried out by using a magnet from the outside with the help of a special nail placed inside the bone. In this technique, the patient is operated once, a controlled fracture is created in the bone, and the lengthening motor inside the nail is operated with the help of a magnet applied over the skin, and a 1 mm lengthening process is performed every day. In the meantime, there is no device outside the patient's body that makes life difficult. When the desired amount of elongation is reached, the new bone (regenerate) formed without a new lengtheningit is expected to mature, that is, the consolidation phase is started, which, as stated above, is roughly twice the time spent in the elongation phase.

Among the questions frequently asked by the patients, the question of how many cm the lengthening surgery can be performed comes first. We have two bones that make up our lower extremity (leg). The first and longer bone is called the femur (our thigh bone that extends from our hip to the knee joint), and the second is called the tibia (our shin bone that runs from our knee joint to our ankle).

With current implant systems, the safe limits for lengthening are 8 cm for the femur and 7 cm for the tibia. There is a 6/4 ratio between the femur and tibia in our body. It is possible to perform lengthening from both bones in order not to deteriorate this ratio, but it is not a preferred method to perform both femur and tibia lengthening in the same session in order not to increase the risk of surgery. Although the ratio of 6/4 is important, there are many patients who are satisfied with lengthening from a single bone, as lengthening processes are time-consuming and laborious.

To sum up, it is possible to lengthen only the femur (8 cm) or only the tibia (7 cm), as well as the lengthening of a person by 15 cm as a result of lengthening operations performed separately from two bones.

To summarize the lengthening techniques and their advantages/disadvantages in short articles:

1. Lengthening with the help of external fixator:
   1. It is the cheapest in terms of cost.
   2. The second advantage is that after the completion of the lengthening process, there is no implant in the body that needs to be removed later.
   3. The biggest disadvantage is having to live outside the body for a very long time (9-12 months) with fixators during the elongation and strengthening of the elongated bone.
   4. During this period, there is a risk of infection at the bottom of the thick nails that reach the bone from outside the body.
   5. Cosmetically, disturbing surgical scars may remain at the bottom of the nails.
   6. During prolonged treatment, the risk of nonunion, delayed union and angular deformity due to mechanical failures is higher than other methods.
   7. Although it is the cheapest method in terms of cost in current lengthening surgeries, its preferability has decreased a lot due to the risk of complications.

1. Combined method (LON-Lengthening on Nail)
   1. It ranks second among the three methods in terms of cost.
   2. It is the most preferred method in our country for economic reasons.
   3. Only in the extension phase of lengthening (approximately 3 months for 8-9 cm) there is an external fixator.
   4. The advantage of the combined method over other methods is that it allows the system to carry more body weight during the extension phase.
   5. After the lengthening process is completed (approximately 3 months), the fixator is removed and the intramedullary nail in the bone is locked. Therefore, there is a need for a second operation within 2-4 months after the first operation.
   6. Due to the thick nails reaching the bone from outside the body and the intramedullary nail placed inside the bone, the infection risk is the highest among the three methods because of the risk of infection in the bone in case the nails in the skin become infected.
   7. Cosmetically, disturbing surgical scars may remain at the bottom of the nails.

1. Since it is a permanent implant in the bone, it is recommended to remove the nail in the bone (after 2-3 years), although it is not essential, after the height increase and the return to normal life.

1. Cosmetic Length Extension with Magnetic Nails
   1. It is the most expensive method in terms of cost.
   2. Since the surgery is made through small incisions, it is cosmetically pleasing.
   3. Both the lengthening and consolidation phases are achieved in a single operation.
   4. With the help of a magnet applied outside the body, the motor in the nail is started and the extension process is performed.
   5. It has the lowest risk of infection.
   6. Since it is a permanent implant in the bone, it is recommended to remove the nail in the bone (after 2-3 years), although it is not essential, after the height increase and the return to normal life.
   7. Two separate implants are used in the magnetic nail.
      1. Exactly 2
      2. Struggles
   8. Although the working principle of the two nails is the same, the material used is different.
   9. Precice 2 is a magnetic nail made of titanium material that has been used for many years. Relatively less costly. However, since titanium is a relatively flexible material, full load bearing is not allowed during both the extension and early consolidation periods. While mobilizing with partial load, transition to full load is allowed as long as it is ensured that the fusion tissue begins to strengthen in the control radiographs.
   10. Stryde is a relatively new nail made of stainless steel. The advantage is that it allows for earlier reloading, but the cost is close to twice that of Precice 2.
   11. The use of Stryde nails in our country is not available so far. It is expected to be put into use in the spring-summer months of 2023.